Ultrasonic-assisted drying is an effective technique for accelerating drying processes, particularly for products with high porosity. The structural changes induced by pulsed electric field (PEF) treatment can make low-porosity products more susceptible to the effects of ultrasound during drying. This study aimed to investigate the influence of PEF treatment on the structure of low-porosity products, such as butternut squash, and to evaluate its effect on ultrasonic-assisted drying. PEF pretreatment altered the physicochemical and microstructural properties of butternut squash. Thus, the higher the energy input, the higher the cell disintegration rate, the lower the shearing force and the lower the water holding capacity. For the same energy input applied, no influence was observed from the different combinations of pulse number and electric field intensity used. The microstructural analysis also showed greater effects with increasing intensity of PEF treatments. All these changes affected the subsequent drying, increasing the drying rate of conventional drying. Moreover, PEF pretreatment enhanced the ultrasound effects when applied during drying, reducing drying time by up to 47% when moderate PEF intensity was used. Therefore, PEF pretreatment under the appropriate conditions could make ultrasound-assisted drying of low-porosity products, such as butternut squash, more feasible.

中文翻译：

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通过脉冲电场 （PEF） 预处理增强低孔隙率产品的超声波辅助干燥：以胡桃南瓜为例


超声波辅助干燥是加速干燥过程的有效技术，特别是对于高孔隙率的产品。脉冲电场 （PEF） 处理引起的结构变化会使低孔隙率产品在干燥过程中更容易受到超声波的影响。本研究旨在探讨 PEF 处理对胡桃南瓜等低孔隙率产品结构的影响，并评价其对超声辅助干燥的影响。PEF 预处理改变了胡桃南瓜的物理化学和微观结构特性。因此，能量输入越高，电池分解速率越高，剪切力越低，持水能力越低。对于施加的相同能量输入，使用的脉冲数和电场强度的不同组合没有观察到任何影响。微观结构分析也显示，随着 PEF 处理强度的增加，效果更大。所有这些变化都影响了后续的干燥，提高了常规干燥的干燥速率。此外，PEF 预处理增强了干燥过程中的超声效果，当使用中等强度的 PEF 时，干燥时间缩短了 47%。因此，在适当的条件下进行 PEF 预处理可以使低孔隙率产品（如胡桃南瓜）的超声辅助干燥更加可行。